ia64/linux-2.6.18-xen.hg

view drivers/mtd/maps/iq80310.c @ 897:329ea0ccb344

balloon: try harder to balloon up under memory pressure.

Currently if the balloon driver is unable to increase the guest's
reservation it assumes the failure was due to reaching its full
allocation, gives up on the ballooning operation and records the limit
it reached as the "hard limit". The driver will not try again until
the target is set again (even to the same value).

However it is possible that ballooning has in fact failed due to
memory pressure in the host and therefore it is desirable to keep
attempting to reach the target in case memory becomes available. The
most likely scenario is that some guests are ballooning down while
others are ballooning up and therefore there is temporary memory
pressure while things stabilise. You would not expect a well behaved
toolstack to ask a domain to balloon to more than its allocation nor
would you expect it to deliberately over-commit memory by setting
balloon targets which exceed the total host memory.

This patch drops the concept of a hard limit and causes the balloon
driver to retry increasing the reservation on a timer in the same
manner as when decreasing the reservation.

Also if we partially succeed in increasing the reservation
(i.e. receive less pages than we asked for) then we may as well keep
those pages rather than returning them to Xen.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Jun 05 14:01:20 2009 +0100 (2009-06-05)
parents 831230e53067
children
line source
1 /*
2 * $Id: iq80310.c,v 1.21 2005/11/07 11:14:27 gleixner Exp $
3 *
4 * Mapping for the Intel XScale IQ80310 evaluation board
5 *
6 * Author: Nicolas Pitre
7 * Copyright: (C) 2001 MontaVista Software Inc.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <asm/io.h>
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/map.h>
22 #include <linux/mtd/partitions.h>
25 #define WINDOW_ADDR 0
26 #define WINDOW_SIZE 8*1024*1024
27 #define BUSWIDTH 1
29 static struct mtd_info *mymtd;
31 static struct map_info iq80310_map = {
32 .name = "IQ80310 flash",
33 .size = WINDOW_SIZE,
34 .bankwidth = BUSWIDTH,
35 .phys = WINDOW_ADDR
36 };
38 static struct mtd_partition iq80310_partitions[4] = {
39 {
40 .name = "Firmware",
41 .size = 0x00080000,
42 .offset = 0,
43 .mask_flags = MTD_WRITEABLE /* force read-only */
44 },{
45 .name = "Kernel",
46 .size = 0x000a0000,
47 .offset = 0x00080000,
48 },{
49 .name = "Filesystem",
50 .size = 0x00600000,
51 .offset = 0x00120000
52 },{
53 .name = "RedBoot",
54 .size = 0x000e0000,
55 .offset = 0x00720000,
56 .mask_flags = MTD_WRITEABLE
57 }
58 };
60 static struct mtd_info *mymtd;
61 static struct mtd_partition *parsed_parts;
62 static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
64 static int __init init_iq80310(void)
65 {
66 struct mtd_partition *parts;
67 int nb_parts = 0;
68 int parsed_nr_parts = 0;
69 int ret;
71 iq80310_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE);
72 if (!iq80310_map.virt) {
73 printk("Failed to ioremap\n");
74 return -EIO;
75 }
76 simple_map_init(&iq80310_map);
78 mymtd = do_map_probe("cfi_probe", &iq80310_map);
79 if (!mymtd) {
80 iounmap((void *)iq80310_map.virt);
81 return -ENXIO;
82 }
83 mymtd->owner = THIS_MODULE;
85 ret = parse_mtd_partitions(mymtd, probes, &parsed_parts, 0);
87 if (ret > 0)
88 parsed_nr_parts = ret;
90 if (parsed_nr_parts > 0) {
91 parts = parsed_parts;
92 nb_parts = parsed_nr_parts;
93 } else {
94 parts = iq80310_partitions;
95 nb_parts = ARRAY_SIZE(iq80310_partitions);
96 }
97 add_mtd_partitions(mymtd, parts, nb_parts);
98 return 0;
99 }
101 static void __exit cleanup_iq80310(void)
102 {
103 if (mymtd) {
104 del_mtd_partitions(mymtd);
105 map_destroy(mymtd);
106 kfree(parsed_parts);
107 }
108 if (iq80310_map.virt)
109 iounmap((void *)iq80310_map.virt);
110 }
112 module_init(init_iq80310);
113 module_exit(cleanup_iq80310);
116 MODULE_LICENSE("GPL");
117 MODULE_AUTHOR("Nicolas Pitre <nico@cam.org>");
118 MODULE_DESCRIPTION("MTD map driver for Intel XScale IQ80310 evaluation board");